Preheating of air for hot-blast stoves of blast-furnaces.



. E. E. MARSHALL.

PREHEATING OF AIR FOR HOT BLAST STOVES 0F BLAST FURNACES.

v APPLICATION FILED APR.4,1916. 1,217,039.

Patented Feb. 20, 1917.

4 SHEET$-SHEET I.

E. E. MARSHALL.

PREHEATING OF AIR FOR HOT BLAST STOVES 0F BLAST FURNACES.

APPLICATION FILED APR. 4, 19H)- Patented Feb. 20,1917.

4 SHEETS-SHEET 2.

E. E. MARSHALL. PREHEATING OF AIR FOR HOT BLAST STOVES 0F BLASTFURNACES.

APPLICATION FILED APR.4, 1916. 11,217,039. Patented Feb. 20,1917.

4 SHEETS-SHEET 3.

E. E. MARSHALL. PREHEATING OF AIR FOR HOT BLA ST STOVES 0F BLASTFURNACES.

APPLICATION FILED APR. 4, 1916. 1,217,039. Patented Feb. 20,1917,

\ 4 SHEETS-SHEET 4.

ram sro w: are vs 670 v4: Jrovs To all whom it may concern:

Beit known that I, EDVFARD E. MARSHALL, a citizen of the United States,residing in enrich.

nnwann E. mansmm,;or PHILADELPHIA, rnnnsrtvaaim.

i PREEATING- OF'AIB FOR HGT-BLAST S TOVES 0F BLAST-iU-ENACES,

Philadelphia, Pennsylvania, have invented certain Improvements in thePreheating of Air for Hot-Blast Stoves of Blast-Furnaces, of which thefollowing is a specification.

My invention rela to the pre-heating of air for blast furnace use, andconsists more particularly of improved means for supplying the hot blaststoves of blast furwith pre-heated air, which air after further heatingin such hot blast stoves is delivered to the blast furnace in a highlyheated state. F or the best results, this air' must be at a relativelyhigh and substantially uniform temperature, and, the usual practiceheretofore has been to utilize the structures familiarly known as hotblast stoves, which stoves contain certain forms of heating deviceswhereby cold or relatively E cold air introduced into the same can behighly heated, and heated to the temperature desired before beingintroduced into the blad furnace.

Various forms of hot blast stoves are em.

ployed in practice but, asmay be readily understood, the introduction ofrelatively cold air or air at atmospherictemperature is highlydestructive of the heating portions of such hot blast stoves; hence thenecesity of comantly repairingportions destroyed by stir-was or breaksoccasioned by the t difierence between the temperatures 0 the incomingand outgoing air. Moreover the use of hot blast stoves for supplying allof the heat necesary for the required amount of air passing therethroughto the blast fun naee necessitates the employment of a large number ofstoves to maintain the desired or required supply of heated air, whichstoves, however, are unable'to impart the really high heat desired toair entering at ordinary atmospheric temperature. When, however, as inmy method of promure. the arsentering the hot blw stove has been raisedapproximately to 600? F'the- Work of the hot blast stove is materiallylessened, withv a consequent reduction of ener necessary to raise it tothe high heat deslred, and. by reason of supplying the blast furnacewith the required amount of highly hwtwalr,

. the amount of fuel required therein for smelting purposes ismaterially le sened.

The object of my invention is to provide Specification of LettersPatent.

-' whereby air at atmospheric temperature may be heated to a relativelyhigh temperature before introduction into. thelhot blast stove, whereinthe temperature of such air.

Patented rep. 2e, tea a. Application filed April a,- 1916. Serial no;cases.

the inlet and outlet of the hot blast stove shall be materiallylessened.A further ob j ject of my invention is to economize the amount of fuelrequired-in the blast furnace for smelting purposes, and further togreatly reduce the time usually required to heat the air employed in theblast furnace in the hot blast stoves. While heating means for thepre-heater may beobtained from any suitable sourcefI preferably. employthe waste gases direct from the blast furnace which are delivered tosuitable burner structures at the inlet end of the pre-heater.

These and other features of m invention are more fully describedhereinafter, reference being had to the accompanying drawings, in which:a

Figure 1, isa sectional plan view of a pre-. heater structure embodyingmy invention;

Fig. :2. is a longitudinal section of the same on the line HH, Fig. 1;

Fig. 3, is a'front elevation of the preheater structure;

Fig. 4, is a vcross sectionaltview on the line IVIV, Fig. 1;

Fig. 5. is an enlarged view of a. portion of the tubular air-passages inthe pre-heater in which the air is heated, and

Fi 6, is a diagrammatic view illustrating die layout of blast furnace,hot blast stoves and pro-heater;

My improved pre-heater structure ma eomprise a substantially rectangularbuil ing 1 of suitable type, preferably of the usual furnaceconstruction, with fire-brick lining &c., and the pre-heater properpreferably'embodieis a pair of units 1* and 1*, which may be workedalternately or simultaneously as may be necessary or desirable. for therequirements of the hot blast stove or stoves, or the blast furnace.

Within the chambers I and 1 of the pro-heater structure, I provideaplurahty of conductors 2 for the heated air, wh ch conductors aresubstantially of inverted U- shape-1n cross section, projectingvertitally into the chambers and having their.

free ends wnnectm to manifolds? so as to I make continuous channels ofatortuous type providing for the heating of a'larw quanm of air.temperature is delivered to Air at 'or about atmospheric theseconductors 2 through pipes a from a manifold 5 which in turn receivessuch air from a blast pipe 6 leading from a suitable-blowing engine ,7,and from said conductors the heated air is led by suitable conduits 8 toa manifold 9 from which it passes to a pipe 10,: thence to lamanifoldreceiver 11, and from thelatter it passes to the inlet ports 12 of thehot blast stove or stoves 13. The latter may receive heated air from theconductors 2 of both chambers 1 and 1", or from either chamberalternately.

The inlet end of the pre-heater isprovided with suitable burners 16arranged to receive, via a conduit 17 the gas dischar ed direct from theblast furnace, which pro erably passes through a dust catcher 15 beforeentering said burners 16, where it is burned for the purpose of heatingthe air to be subsequently delivered to the blast fur nace; the'flamefrom such burners being delivered to or discharged into the chambers land 1 of the pro-heater structure around I the conductors 2.

The quantity of the air to be heated which is introduced, into themanifolds 30f the conductors 2 from the pipes 4, is controlled by valves19, and the conduits 8 are provided with valves 20 whereby delivery "ofthe heated air to the several pipes for passage to the hot blast stoveor stoves may be controlled or regulated.

By my improved arrangement and con I struction of pre-heating means, Iam enabled to use the waste gases direct from the,

blastfurnace to raise the temperature of the air no such pro-heaterstructure, which preheated air is delivered .to the checker brick hotblast stoves. In this way air at a very high temperature is delivered tothe hot blast stoves wherein it is heated to a much higher and desiredtemperature with the consequent result that as the incoming air is hot,it'does'not have to be raised from a low temperature to a hightemperature in the hot blast stoves but being at a relatively hightemperature upon entrance into the hot blast stoves it may be quicklyraised therein to the desired temperature before passing to the blastfurnace. This extra heating can be effected in a much shorter time thanthe entire heating usually performed by the hot blast stoves, and as the"high temperature highly heated. As suchnecting the hot mimosa tionablecooling by theneception of" air at atmospherictemperature, their lifeisgreatly prolonged and their value as heating means is greatlyincreased.

Furthermore, T am enabled by. my particular arrangement to impart ahigher and more uniform degree of heat for a longer period, with'theadditional advantage of thereby reducing the consumption of fuel in' theblast furnace. The greater the temperature of the air delivered to theblast furnace, coupled with uniformity of such in the continuing volumedelivered, the less fuel will be required to overcome the variation intemperature necessary to raise the heat in such furnace to the smeltingpoint. A further feature of economy is that the pre-heating of the airaccording to my arrangement enables me to cut down the capacity ornumber of the hot blast stoves, and inasmuch as the number of stoves (orhot blast stove capacity) can be reduced, the cost of plant equipment isproportionately reduced.

ll claim:

1. The combination with a blast furnace and hot blast stoves employedtherewith, of a pre-heating device for air, means for delivering heatedair from said pre-heating device to said hot blast stoves, a connectionbetween the furnace and the pre-heater for the passage of waste gasdirect to said preheating device, burners for the latter discharginginto said preheater, a conduit connecting-the hot blast stoves with theblast furnace, and valves controlling the passage of air to and fromsaid hot blast stoves.

2. The combination with. a blast furnace and hot blast stoves employedtherewith, of

device to sald hot blast stoves, a connection between the furnace andthe ore-heater for k the passage of waste gas direct to said preheatingdevice, burners for the latter discharging into said pro-heater, aconduit conblast stoves with the blast furnace, and valves controllingthe passage of air to and from said hot blast stoves.

3. The combination with a blast furnace andhot blast stoves employedtherewith, of an air pro-heater, furnace and the pre-heater for thepassage a connection between the of waste gas direct to said pre-heater,con- 7 nections between the furnace and the hot blast stoves fordelivering waste gas thereto independently of such delivery tothepreheater, burners-mounted in the pre-heater for the combustion of thewaste gas de-' livered thereto from the blast furnace; said burnersdischarging their flame into the chambers of the pre-heater, means fordelivering heated air from said pre-heater to (50 ter, burners or thecombustion of thewaste 'gas dehvered to the ing located between the'hotblast stoves and,

the furnace, a plurality of air conductors ered to the pre-heatingdevice from the blast the hot blast stoves including ipressilrej means,a conduit connecting the hot'blast stores with the blast furnace, andvalves nace and hot blast stoves therefor, ofa pre heater in which airis heated by; the waste:

gases direct from the furnace,.- said "preheater being'located betweenthe hot blast stoves andthe furnace, a plurality of air; conductors insaidpre-heater, and valves; controlling the inlet and discharge of airto and from said Dre-heater.

heater in which air is heated by the"was'te gases from the furnace, said'pre-heaterbev in said pre-he'ater, valves controlling the inlet anddischarge of air to and from said pre-heater, and a blower fordelivering air to the pre-heater and continuously dischar'ging the airheated therein to the hot blast stoves. a

ends of said tubes, a ,valved conduit for, leading a1r to said tubes, avalved conduit for leading heated air from said tubes, burners fordlscharging flame into said heating chambers, and means for deliveringwaste gas direct from the blast furnace to said burners.

posed between the latter and a blastfur into-said chamber, manifolds forthe lower ends of said tubes, a valved conduit for'lead-f ing air tosaid tubes, a valved conduit. for

leading heated air from said tubes, a blower waste gas from the blastfurnace .to said burners. v a 8. Ina system for heating air forblastfurnaces and passing the same thereto via hot blast stoves employedtherewith, the combination ofta pres eating-device for air, means fordelivering air under pressure to said pre-heating device, a connectionbetween the furnace and the pre-hfe'ating device for the assage of wastegas-to the latpre-heating device from the blast furnace; said burnersdischarging their flame directly into said pre-heatin device and-theheated air, from said .pre-h the 5. The combinatiomiwith a smelting naceand hot blast stoves therefor, of a pm I "blast stoves for deliveringwaste gas therea to independently of the delivery of such waste gas tothe pre-heating device, burners previouslyintroduced iti'to thepre-heater, 1

means afi'ording communication between the hot blast stoves andthelblast' furnace, and," means for controlling the passage of theheatedair to and from'said hot blast stoves. I I

' 9Q In a systemfor heating air for blast furnaces and passingthe samethereto via hot blast-stoves employed therewith, the

combination ofa preheating device for air,

means-for delivering air under pressure to said Ipixieaheating device, aconnection between nace and the pre-heating device for the passage of,waste gas direct to the latter,

connections between the furnace and the hot for the combustion of thewaste gas delivfurnacej; said burners, discharging their flame directlyinto said pre-heating device 1 and the heated air from said pre-heatingde vice being delivered to" the hot blast stoves 955 v i r by the samepressure means which previ-r 6. In -a pre-heater for hotblast stovesdisously'introduced ittothe pre-heater, means I I blaststovesand theblast furnace, and means for controlling the passage of the heated airinto said chamber, manifolds for the lower 1 to and from said hot blaststoves.

affording Jcommunic'ation'between the hot 4 a --'i10. Ihe method of-vheating air for the blast of a smeltingor other furnace, which consistsin delivering airunder pressure to a conduit disposed-within acombustion chamber-coincident with the delivery to, said chamber ofwaste gasidirect from said blast the air in said combustion chamber insup- 1-.porting the combustion of the waste gas nace, the combmatlonofa'chamber, a,p1urahty of heatlng' tubes projecting vertically wherebythe air in the conduit within said combustion chamber is highly heated,delivering such heated air to a hot blast stove, raising the temperatureof such heated air in the hot blast stove, and finally delivering saidtwice heated'air to the smelting furnace. i

11. The furnaces and passing the same thereto via; hot blast 'stovesemployed therewith, which I furnace,-utilizing azpoi'tionof the oxygenof 7. In a pre-heater for hot blast stoves, dis

method of heating air-for blast 7 comprises the deliveryof air underpressure" direct fromthe furnace to said eating element, burning thewaste gas delivered to the tion between the hot blast stoves and the toa heating element, deliverin wastegas blast furnace, and controlling thepassage of the heated air to and from the hot blast stoves a .12; lhemethod of heating ,air for blast furnaces and passing the same theretovia hot blast stoves employed therewith, which comprises the delivery ofair under pressure .to a heating element, delivering waste gas gas tothe hot blast stoves, burning the waste gas delivered to the heatingelement whereby, the flame from such combustion 1-) may discharge intothe interiorthereof; the

so heated air being delivered to the hot blast stoves by the samepressure which previously introduced it to the heating chamber, pro

viding communication between the hot blast stoves and the blast furnace,and controlling the passage of the heated air f ing .elementto the hotblast sto es and from the latter to the blast furnace; I

EDWARD 'E. MARSHALL.

cm the heatp

